Remote controllers are important components of many electrical devices such as TVs, DVD players, air conditioners, home theater systems. Nowadays, remote controllers are also used to control the lighting of the house. The use of remote controllers facilitates the controlling process since the user can control the device remotely. However, a user still needs to find and pick up the remote controller before he or she can control the device. In addition, many different remote controls are already present in the room for multiple electronic devices. Further, the different buttons on a remote control can be confusing to the user. Finally, the costs of a remote control and the accompanying receiver can be relatively high.
It is desirable to reduce the dependence on remote controller while still providing simple and easy control devices. For example, lighting systems being controllable remotely without controllers have been demonstrated. For example, a lighting system may comprise an infrared transmitting and receiving unit. The distance between the user hand and receiving unit can be determined by the intensity of the infrared light reflected by the user hand and received by the receiving unit. The brightness or the color of the light output can be adjusted by changing the distance between the hand and the lighting device. In this manner the lamp can be dimmed by the hand position in front of the infrared beam. Such an arrangement is however relatively inaccurate, as the intensity of the reflected infrared signal heavily depends on the kind of object that is moved in the beam. Other disadvantages include that the hand position can only control one attribute of the light, i.e. the brightness, and that complicated gestures cannot be differentiated and recognized. Furthermore, the user needs to face toward the sensor in order to successfully control the device. In cases where in the light and the sensor are separated by a large distance or a wide angle, it is anti-intuitive to control a light by doing gesture in a direction not toward the light. Other disadvantages may include the inability to accurately select and control multiple light units.